3D smooth path planning for a UAV in cluttered natural environments

This paper presents a 3D path planing algorithm for an unmanned aerial vehicle (UAV) operating in cluttered natural environments. The algorithm satisfies the upper bounded curvature constraint and the continuous curvature requirement. In this work greater attention is placed on the computational complexity in comparison with other path-planning considerations. The rapidly-exploring random trees (RRTs) algorithm is used for the generation of collision free waypoints. The unnecessary waypoints are removed by a simple path pruning algorithm generating a piecewise linear path. Then a path smoothing algorithm utilizing cubic Bezier spiral curves to generate a continuous curvature path that satisfies the minimum radius of curvature constraint of UAV is implemented. The angle between two waypoints is the only information required for the generation of the continuous curvature path. The result shows that the suggested algorithm is simple and easy to implement compared with the Clothoids method.